1. Field of the Invention
The present invention relates to an art of providing an electric power converter for supplying electric power to a motor, for example.
2. Description of Related Art
JP-A-6-38546 discloses cooling of an electric power converter (particularly see FIG. 1, and page 2). In JP-A-6-38546, by varying the length of a cooling fin at its circumferential part and at its inner part, it is intended to further improve cooling capability as compared to a conventional one. In the electric power converter, a conversion loss is generated in a diode bridge, and in a transistor module and an IGBT module which are inverse transforming elements, to generate heat. The heat generated due to the conversion loss is dissipated from the cooling fin by wind generated using a cooling fan so as not to thermally destroy semiconductors such as the diode and transistor. In general, it is said that silicon composing a semiconductor is destroyed when the temperature of the semiconductor becomes 150° C. or more, and therefore cooling is performed so that the temperature is equal to or below 150° C.